docs: def parse_xml_boundary(xml_region):
          """
          Get the geographic bounds from an XML element
  
          Args:
              xml_region (Element): The <region> tag as XML Element
  
          Returns:
              GeographicBB:
          """
          try:
              bounds = {}
              for boundary in xml_region.getchildren():
                  bounds[boundary.tag] = float(boundary.text)
              bbox = GeographicBB(min_lon=bounds["west"], max_lon=bounds["east"],
                                  min_lat=bounds["south"], max_lat=bounds["north"])
              return bbox
          except (KeyError, ValueError):
              raise MapSourceException("region boundaries are invalid. ")